Eurosceptic political parties have gained substantial support in democratic elections. Scholars have widely studied their programmatic positions. We know much less about the behaviour of Eurosceptics within legislatures. How does Eurosceptic contestation translate into voting behaviour? How do members of Eurosceptic parties engage in plenary debates? Do they stick to their peers when they vote and debate or do they form an untidy opposition? We expect Eurosceptic contestation to be weaker in policy fields that are less structured along the new cultural cleavage and are dominated by left-right ideologies or national interests. Our chapter develops this argument and offers an empirical study of Eurosceptic polarisation and Eurosceptic cohesion in the European Parliament (EP). We present an analysis of roll-call votes in the 7th and 8th legislative term of the EP (2009–2019). Six case studied then zoom into selected legislative processes in three policy fields to explore how contestation materialises in committee work and parliamentary debates in different policy fields. Our findings on cross-sectoral differences allow for a more differentiated understanding of Eurosceptic contestation becoming a vital feature of democratic practices rather than undermining EU policy-making, and European integration more broadly.